Lamina Cribrosa Morphology in Normal-tension Glaucoma According to the Location of Visual Field Defects.

Abstract

The morphological alterations in lamina cribrosa may be related to the location of visual field defects. The aim of this study was to investigate morphologic differences in the lamina cribrosa (LC) in normal-tension glaucoma (NTG) according to the location of visual field (VF) defects. This study was a retrospective, cross-sectional study. Ninety-six eyes of 96 patients with NTG were included in this study. The patients were divided into two groups according to the location of VF defects (parafoveal scotoma [PFS] and peripheral nasal step [PNS]). All patients underwent an optical coherence tomography (OCT) of the optic disc and macula using swept-source OCT (DRI-OCT Triton; Topcon, Tokyo, Japan). The parameters of the optic disc, macula, LC, and connective tissues were compared between the groups. The relationships between the LC parameters and other structures were analyzed. The temporal peripapillary retinal nerve fiber layer, average macular ganglion cell-inner plexiform layer, and average macular ganglion cell complex were significantly thinner in the PFS than in the PNS group (P<0.001, P<0.001, and P=0.012, respectively). The PFS group showed a more glaucomatous LC morphology with a smaller lamina cribrosa-global shape index (LC-GSI, P=0.047), more LC defects (P=0.034), and thinner LC (P=0.021) than the PNS group. LC-GSI was significantly correlated with LC thickness (P=0.011) but not with LC depth (P=0.149). In patients with NTG, those with initial PFS showed a more glaucomatous LC morphology than those with initial PNS. The morphological differences in LC may be related to the location of the VF defects.